In power distribution systems, widely used are distribution facilities whose facility capacity can withstand a peak load. The facility capacity of such a distribution facility is determined based on a peak load current derived in installation of the distribution facility. Every time the load state is changed after the installation or the distribution facility is replaced because of aging, the facility capacity of the distribution facility is determined based on the latest load state. Conventional technologies are described in Japanese Laid-open Patent Publication No. 2007-080260, for example.
Distribution facilities, such as transformers, consume electric power themselves. The electric power consumed by the distribution facilities is generated and then consumed while being transmitted to a consumer. Because the electric power is not used by the consumer, it is considered as a loss. Such power loss in a distribution system is referred to as a distribution loss. The distribution loss increases as the distribution capacity of a distribution system decreases. When the distribution capacity of the distribution facility decreases depending on the load, the distribution loss increases.
It has been difficult to grasp the electric current value in each distribution facility of the distribution system, and thus the distribution loss of each distribution facility has not been grasped with high accuracy.